The present invention relates to a plasma processing apparatus that processes a board-shaped sample, such as a semiconductor wafer placed on the top face of a sample stage disposed in a processing chamber using plasma formed in the processing chamber in a vacuum container in the process step of producing a semiconductor device, and specifically to a plasma processing apparatus that processes a wafer placed on the top face of a sample stage while the temperature is adjusted by a thermoregulator, such as a heater, disposed in the inside of the sample stage.
Conventionally, to a plasma processing apparatus that subjects a film layer disposed on the surface of a semiconductor wafer (in the following, a wafer) to processing, such as etching, and produces a semiconductor device, it is demanded to provide the reliability of processing that enables the miniaturization or high precision processing of the film layer on the wafer surface or enables such processing with the restraint on variation in the processed result for a long time. It is also demanded to improve the efficiency of processing and improve the number (the throughput) of wafers to be processed within a unit time.
In order to solve such problems, in the conventional plasma processing apparatus, an apparatus having a configuration including a temperature regulator is thought. The temperature regulator is disposed in the processing chamber in the inside of the vacuum container where a wafer is processed, and the temperature regulator enables the regulation of the temperature of the top face of the sample stage or a wafer placed on the top face to temperatures in desired range. Alternatively, an apparatus having a configuration is known in which the space in the inside of the processing chamber is in axial symmetry, the variation in the evacuation from the processing chamber and the variation in the density of products, for example, generated in the processing chamber and evacuated to the outside of the processing chamber with the evacuation about the center axis can be reduced.
An apparatus having a structure of a processing chamber is thought in which the eccentricity of a passage in the processing chamber through which particles, such as a gas or plasma, flow is reduced and the velocity or amount of the flow is made equally close in the circumferential direction. In order to improve throughput, an apparatus including a so-called multi-chamber is known in which a plurality of processing chambers where wafers are processed is coupled through a transfer chamber that transfers wafers in its inside, or an apparatus including a configuration is known in which transfer chambers are coupled with a relay chamber that can accommodate wafers in its inside.
As an example of such a plasma processing apparatus or a vacuum processing apparatus, an apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2005-101598 is known.
On the other hand, in order to achieve high integration of semiconductor devices nowadays, many kinds of materials and a variety of integrated structures are being used in semiconductor devices. In order to cope with such trends, plasma processing apparatuses in various methods are being developed. For plasma generation in such plasma processing apparatuses, the inductive coupling method, the electron cyclotron resonance method, and the parallel plate method (including the magnetron method) are mainly used. Typically, for the electron cyclotron resonance method, electric fields in an electromagnetic wave band of 2.45 GHz or the VHF band in a range of about 30 to 300 MHz (more preferably, 30 to 200 MHz) are used, and in the inductive coupling method and the parallel plate method, electric fields in a radio frequency band of 13.56 MHz are mainly used.
As a typical plasma processing apparatus that generates plasma by the parallel plate method, a typical apparatus includes a disk-shaped upper electrode and a lower electrode. The upper electrode is disposed covering a processing chamber in the inside of a vacuum container from above, and electrically connected to a radio frequency power supply that supplies electric power at the radio frequency described above. The lower electrode in a disk or a cylindrical shape is disposed in the inside of a sample stage below the processing chamber, and the upper electrode and is disposed opposite to the top face of sample stage. The lower electrode is supplied with electric power at a frequency smaller than the frequency of radio frequency electric power for forming plasma. The apparatus includes a conductor disposed below the bottom face of the upper electrode and configuring the ceiling face of the processing chamber or a dielectric shower plate having a plurality of gas inlet holes through which a processing gas is introduced into the processing chamber. Using the processing gas, plasma is formed in the processing chamber between the upper electrode and the lower electrode, and a wafer placed on the top face of the sample stage is processed. As an example of such a plasma processing apparatus, an apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2016-162266 is known.